• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Describe the differences between natural ecosystems and agro-ecosystems

Extracts from this document...


Describe the differences between natural ecosystems and agro-ecosystems An ecosystem is by definition the processes and interactions of the biotic community (living organisms) and inorganic component (physical and chemical features) of a particular environment. In a natural setting a stable, or climax ecosystem represents a state of natural equilibrium, whereby all occupant species compete for resources, and energy and nutrient cycles are balanced. Human farmers effectively out-compete most natural species for resources, and through select harvested species export energy and nutrients for consumption elsewhere; this is an agro-ecosystem or plagioclimax. An ecosystem unaffected by man has a structure characteristic of its climatic region, for example deciduous oak woodland in the U.K has a typical biomass of 30Kgm-2, and an average productivity of 1.2Kgm-2 per year. This reflects the maximum mass of flora and fauna that can be supported by the climate and soil. However, when such woodland is cleared and tilled by man new characteristics appear. Arable crops have a far lower average biomass, wheat is typically 1.6Kgm-2, with productivity falling to 0.6Kgm-2 per year. This is caused by the loss of the multi-storey vegetation that photosynthesises at maximum scale and optimum rate, and in arable fields there is not the habitat to support faunal species such as woodpeckers and other woodland birds, resulting in lost animal mass. Livestock farmland is characterised by similar primary productivity as grassland, but again this is far below the potential for the temperate climate and fertile soils. ...read more.


Not all farming methods require such drastic alterations to natural cycles, and shifting cultivators, nomadic pastoralists and hunter-gatherers use extensive agricultural techniques that mimic sustainable natural systems, and are successful in supporting small, low-density populations in places such as the Amazon rainforest and Papua New Guinea. Nonetheless, the majority of the human population relies upon intensive settled agriculture, and carefully controlled agro-ecosystems. The environmental impact of such reliance is significant, with even natural ecosystems experiencing feedback from the action of farmers. Examine the environmental impact of intensive farming Agriculture has had a widespread effect on every aspect of the environment, and since 1945 traditional agriculture in the U.K and in industrialised countries worldwide has become increasingly intensive. The means by which such reliable high yield crops, with no requirement for crop rotation are maintained is primarily through the application of a cocktail of agro-chemicals, and each chemical family has a range of impacts on the environment. Fertiliser use is possibly most significant, as the relative fertiliser use is much greater than any other artificial supplement to crops, and application has increased five-fold since 1930 due to the trend towards intensive productivist agriculture. The countryside around Saint-Brieve and the Gou�t basin in Brittany has been subject to severe negative effects of inorganic NPK overuse on vegetable cash crops since world war two. Runoff during rainfall is a major problem, with concentrations of nitrates and phosphates in the Gou�t River reaching very high levels. The high nitrate concentration especially has resulted in eutrophication in tributaries and slower moving waterways, with abnormally rapid algal growth. ...read more.


The result is a soil that may have a lower field capacity and be more susceptible to wind or water erosion. The rapid removal of nutrients, if exceeding the rate of nutrient replacement by fertilisers or farmyard manure can generally reduce soil fertility and hinder plant growth. The pressure of heavy tractors can compact and deform soil structures, and this is particularly pronounced with wet soils, when structural or particle bonding is weakest. Compaction in such a way reduces the size and amount of pore spaces in the soil, reducing aeration and drainage of the soil. This can cause high runoff and exasperate soil erosion in intensively farmed areas, and is a suggested cause for surface gulley erosion that is widespread in East Germany. Intensive industrial farming is also demanding of fuel, and farm processes contribute a significant amount to carbon dioxide emissions that may lead to global warming. It could, however, be argued that with the exponential growth of the human population intensive agriculture in the long-term reduces the rate at which new areas of land have to be cultivated, effectively reducing the need for extensification and environmental damage. However, the opposing argument suggests that if farming was not only extensified, but also made sustainable, then the positive ecological gain would outweigh the loss of some natural habitats. Technology has provided few suggestions as to how intensive productivist agriculture could be replaced, and the protest against GM crops is narrowing down current alternatives. The impact of modern farming on the environment is certainly damaging, but it provides a tangible and potentially successful solution to the worlds hunger. ?? ?? ?? ?? 14/10/05 Henry Munby 1 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Living Things in their Environment section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Living Things in their Environment essays

  1. What Factors are responsible for the success of Insects?

    Similarly locust swarms can arise within a matter of weeks and may contain up to 10 billion individuals (Berenbaum, 1995). All these factors contribute to give a high level of genetic heterogeneity within an insect species. Because reproduction occurs so quickly and in such great numbers a lot of new

  2. Extended Experimental Investigation - Natural Antibiotics

    When the antibiotic properties of this mixture were tested against S. Albus the mixture was more effective than the lemon/garlic mixture previously tested and proved the alternate hypothesis to be correct, though there was no major improvement for E. Coli.

  1. Soil erosion

    In some farming areas of Victoria there is poor regeneration of Red Gum trees because any of the new growth is grazed by sheep. Trees on farmlands can not regenerate if grazing of the new growth continues, and consequently the old trees will die and so will some of the

  2. The comparison of bacterial content in a range of milks.

    Colonies growing on the surface also can be used to inoculate fresh medium and prepare pure cultures. To improve technique, I practiced these methods on the plates to improve my skills and to find the most comfortable and affective method for my experiment.

  1. Investigating the effect of four antibiotic agents on gram positive and gram negative bacteria.

    * Tape petri dishes after inoculation and label the base clearly with name, date and nature of inoculum to avoid microorganisms escaping into the environment if the dish should be dropped and pathogens can be easily identified if contamination occurs.

  2. "What is the significance of the nitrogen cycle in ecosystems? Using suitable examples, discuss ...

    They invade the root hairs and cause the production of an infection thread in the root hair cell (Heriot-Watt University, 2002). This enables the bacteria to penetrate deeper into the root tissue and infect the cells there. The infected root cells become enlarged and undergo rapid division to form a mass of cells called root nodules.

  1. Should cannabis be legalised in the UK?

    Adults in possession of cannabis Anyone caught in possession of cannabis could be arrested. Alternatively, police may: * issue a warning (primarily for first-time offenders) * issue a penalty notice for disorder, with an on-the-spot fine of �80 Need to include arguments for/ against legalising cannabis.

  2. How different methods of farming provide plants with what they need(TM)- comparing methods of ...

    By rotating crops you help disrupt the life cycle of the pests and diseases that will in turn destroy them. Organic and synthetic fertilisers Compared to synthetic fertiliser combinations, organic fertilizers contain less nutrient values however perform important functions that the synthetic formulations do not.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work